A Virgin Atlantic incident earlier this week, in which 15 passengers had to be treated in hospital after an emergency landing evacuation, was due to "a number of alarms being triggered in-flight", the airline said today.
Passengers spoke of people landing on top of each other after the Florida-bound Virgin plane was evacuated at Gatwick having had to turn back to the West Sussex airport on Monday.
Virgin said today the crew of the Airbus A330 had taken positive action in line with procedures by returning to Gatwick and evacuating the plane which has now been certified for a return to service.
All Gatwick flights were suspended for around an hour and 40 minutes while the drama involving the plane, carrying 304 passengers, was being played out.
A Virgin Atlantic spokesman said: "We can confirm that the investigation following Monday's incident on flight VS27 from London Gatwick is now complete.
"A full technical evaluation and systems assessment has been completed in conjunction with the airworthiness authorities and the manufacturer, and the aircraft has been certified for a return to service.
"The investigation identified that a number of alarms were triggered in-flight, in response to which our flight crew took positive action in line with procedures by returning to Gatwick and completing an evacuation of the aircraft."
The spokesman went on: "The flight crew and cabin crew followed safety procedures at all times and carried out their duties in a professional manner to ensure the safety of our passengers was maintained throughout the flight and during the evacuation.
"We again apologise to all of those passengers that were impacted by this difficult but rare situation."
After the evacuation, one passenger, Tom Aldridge, said: "The people panicking as they were jumping off were throwing themselves out of the plane down the chute and there was a big pile of bodies at the bottom where people were just landing on top of each other and there were quite a few injuries."
Fellow passenger Kirsty Bonwick said: "A lot of people were hurt, scraping their arms and legs and elbows and bleeding.
"You think you're going to stop at the end of the chute and then get up, but you go flying off it and you just went across the concrete, which is why everybody cut their arms and legs and were bleeding."
Passenger Mandy Whitton, 47, from Orpington in Kent, told the London Evening Standard there was "complete chaos" among passengers and crew when the captain ordered everyone to evacuate.
She went on: "I really thought it was the end and there we were all going to die. Everybody was petrified."
The incident is being looked at by the Air Accidents Investigation Branch, which will publish a report.